I recently downloaded the new 10.x version of TOAD and could not connect to my databases. Still running TOAD 9.x, no problem. This really threw me off for a minute, so I thought I would share the resolution.

You are likely running a 64-bit Windows OS and have installed TOAD into C:\Program Files (x86)\....

I simply copied over my entire Quest Software directory from C:\Program Files (x86)\... to C:\Program Files\..., and restarted the TOAD.exe. Everything is working great, without having to reinstall anything.

PS: Not sure who to blame here. Vendors (like Oracle and TOAD) should know Microsoft is capable of doing strange things with important directory names (using spaces and, in this case, “strange” characters like parentheses)…and of course, Microsoft should simply stop perpetuating the use of these characters in important directories.